Those sorts of thing sound great for watering a few pots. Could probably work well for the rhubarb with a dripper somewhat near each plant and under the shade of its leaves, they they are large and spaced out. Attempting to grow some tree kale which could probably use it too. I presume you balance the drip rate to keep the area of soil moist but not soaked.
But I also have things growing that are spread out more like walking onions, garlic, jerusalem artichokes. There isn't really a clear point to water for these and they take up a fair sized area.